Robot vacuum cleaner



FIG. 1 is a front, right side, perspective view of a robot vacuum cleaner showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top view thereof.

The bottom view, which is omitted, forms no part of the claimed design. 

CLAIM The ornamental design for a robot vacuum cleaner, as shown and described. 